Weighing instruments measure the mass of an object by measuring its weight. In a strain-gauge balance, the electrical properties of materials change when the material is stressed by either compression or extension as a result of a change in length, cross-section, and specific resistance. Strain-gauges are usually positioned at four different points in a double bending beam. Because a double bending beam incorporates parallel guides, it counters the effects of torque resulting from off-center loading. A value for a weight and therefore a mass is derived from the voltage generated when the four strain-gauges form part of a Wheatstone bridge.
The idea of strain-gauges, that is, measuring the stress, caused by the weight of an object on the structure supporting the object, is also used in several scale designs capable of handling varying weights. Larger loads, for example, may be measured by testing the deformation and stress on a solid cylindrical "spring body." This type of scale can handle loads in excess of a ton.
Weighing scales, weighing instruments or balances of this kind are known from, for example, German Patent Application DE 44 27 088 A1 (U.S. Pat. No. 5,719,357) or, with the exception of the integral construction for the load receptor, guides and system carrier, also from German Patent DE 20 09 858 C1 (U.S. Pat. No. 3,667,560).
It is a disadvantage of the known constructions that the weighing system or scale requires relatively large space.